Former world 1500m champion Elijah Manangoi has been provisionally suspended over an alleged whereabouts failure.
The 27-year-old Kenyan won gold at the 2017 World Championships in London, having claimed silver in Beijing two years earlier.
He was one of four Kenyan athletes who the Athletics Integrity Unit (AIU) announced on Thursday had been suspended or provisionally suspended pending a full hearing.
Manangoi responded on his Facebook, saying it was "devastating" news.
"News of my suspension by the AIU for three missed tests is really devastating for me and I'm trying to get my head round it," he posted.
"What I can say is each of the missed tests happened during 2019, my case has nothing to do with prohibited substances and I've always competed as a clean athlete.
"Last year was the worst period of my career when I was upset through injury which impacted everything on and off the track.
"I know I've let people down, in particular my coach and fellow athletes, and I also know that no matter what I say here I'll be criticised.
"The facts of the cases are clear in my mind and I'm sure there will be a time when it is appropriate to go into more detail.
"But right now I'm focused on compiling a formal response to the AIU so won't be commenting further."
Under anti-doping regulations, athletes have to inform testing authorities of their whereabouts
for a one-hour window of every day.
Three failures in 12 months - not being present at the said time, or filing inaccurate or incomplete information, counts as one failure - and leads to an automatic ban.
There was also a provisional suspension for long-distance athlete Patrick Siele after he was alleged to have evaded, refused or failed to submit for a sample collection.
Mercy Kibarus was banned for eight years after testing positive for an anabolic steroid, a second doping offence within a 10-year time frame.
Kenneth Kipkemoi was also suspended but for two years after testing positive for terbutaline.